The objective of this study is to determine if the implementation of guidelines utilizing immediate CT Perfusion and CT Angiography in addition to non-contrast CT alters (reduces or increases) the time to decision-making for or against rt-PA in acute ischemic stroke, and by extension, time to therapy in treated patients and time to transfer from the department for all patients. A secondary objective is to determine if using CTP/CTA-inclusive hyperacute stroke guidelines improves safety by decreasing symptomatic intracerebral hemorrhage and mortality in patients who receive rt-PA.